Patent GB-886327-A (GB)
Title: Improved multiple speed power transmission mechanism
IPC: F16H61/02
Filed: 1959-05-12
Abstract: 886,327. Change-speed control. FORD MOTOR CO. Ltd. (Ford Motor Co.). May 12, 1959, No. 11122/61. Divided out of 886,326. Class 80 (2). [Also in Group XXXI] In a change-speed gear providing ten forward ratios, two reverse ratios, neutral and park, and comprising planetary trains controlled by three brakes and three clutches, interlock valves are provided in the lines to two brake servo cylinders and prevent the application of one brake until the other brake has been released. A pump 48 supplies liquid through a line4 62, control valves 440, 442 and interlock valves 410, 366 to servo cylinders 318, 402 of brakes 106, 136. The brakes are released by pressure in the servo cylinders and are engaged by springs. Mechanical connections between the valves 410, 366 and the respective servo pistons actuating the opposing brakes ensures that a valve is opened to permit exhaust of liquid from the servo cylinder to apply the associated brake only after the other brake has been released. The pump 48 also supplies liquid through lines 470, 492, and control valves 444, 446, 448, 450 to servo cylinders 96, 126, 146, 286 controlling respectively first, second and third clutches and a brake 86, pressure in a servo cylinder engaging the associated clutch or brake. A valve 472 ensures a delay in the pressurizing of these servo cylinders so that they are actuated only after the actuation of the brakes 106, 136. Application of the brake 86 is further delayed by a restriction 502, quick release of the brake being ensured by a non-return valve 310. A power take-off clutch servo 28 is supplied by the pump 48 through line 470, a control valve 508 and a line 196, and a valve 506 provides a pressure differential to enable the take-off clutch to be engaged during operation of the transmission. A feathering valve 478 is provided downstream of the valve 472 and has a manually-operated spool 480 having a land 482 controlling admission of liquid to the line 492. A plunger 486 controlling an exhaust port 490 is subject to the pressure in the line 492 acting against a spring reacting on the valve spool. On raising the spool to admit liquid to the line 492 the pressure in this line is gradually raised as the spring is compressed. The control valve 508 for the power take-off clutch is similar in construction to the feathering valve. The pump 48 also supplies liquid to a lubricant supply line 520 through a relief valve 510 and a lubricating pressure-regulating valve 514. The control valves 440, 442, 444, 446, 448, 450 are actuated by cams on a common cam-shaft 534 actuated by a cable drive from a manual selector lever. The selector lever is associated with an indicating device and with a switch preventing starting of the vehicle engine except in the " park " position of the selector lever. The drive can be interrupted by moving the feathering valve so that its land 484 blocks the passage 492 and the vehicle may be started in any ratio by manipulation of the feathering valve with the selector lever in an appropriate position. Restrictions 466, 468 by-passing the interlock valves 410, 366 have no effect during gear shift but ensure that the brakes 106, 136 are applied when the vehicle engine, and thus pump 48, is stopped.